Radio receiving apparatus



Jan; 1, 1924 O. MINTON RADIO RECEIVING APPARATUS Filed Jan@ 19, 1923- NNO ATTO EY.'

Patented Jan. I, 1924.

UNITED sTATEs PATENT OFFICE, i

immo itEoEiviNG Arrami'rus.

fappucationiuea January i9, i923. serai No. 613,576.

To all whom it may concern: Y.

Be it vknown that I, OGDEN MiN'roN, a citizen of the United States, residing at Greenwich, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Radio Receiving Apparatus, fully described and represented in the following specification` and theaccompanying drawingforming a part of thesame.

'This invention relates to radio receivin apparatus, and aims to provide a simple andL compact apparatus by eliminating the aerial or loopwhich is customarily a part of such apparatus.

In accordance with the invention the loop or aerial of an ordinary radio receiving apparatus is replaced byA a grounded circuit containing a variable inductance, and most desirably also a variable condenser. The inductance may be provided by two inductance coils positioned for mutual inductance and connected inseries. The two ends of the coi1s`which are connected together are grounded.

In order that my inventionmay' clearly be understood, I will describe in detail a. specific apparatusembodying it. Such an apparatus is illustrated diagrammatically in the drawings, in which l Fig. 1 shows the use of a standard amplifying and detecting system as a part of' the apparatus; and

` Fig..2 shows a modified form of grounded circuit which may be connectedto the amplifying and detecting system shown in Fi 1. pparatus' embodying the invention includes a grounded circuit, the nature of' which is hereinafter explained, connected across the in-put terminals of a detecting system. The detectingv system S which is shown inY Fig. 1, for the sake of illustration, is of a standard type heretofore commonly used in loop receiving apparatus. The detecting system illustrated, which may more specifically be termed a vacuum tube amplifying and detecting system, provides for three stages 4of ra io frequency am-- plification, and two stages of audio frequency amplification. `As the nature and connections of such a system are well understood and clearly illustrated in theI draw' ing, theyare not herein described in detail,

as they do not in themselves form a part of the invention.

The amplifying and detecting system S is,

provided with two in-put terminals Gand F. The terminal lG is connected to the grid element of a three-element vacuum tube V,

while the terminal F is connected through the usual A battery with the ilament` element of'this tube.

Across the in-put lterminals G, F of amplifying and detecting system S- is contwo inductance coils 11, 12. One end 13 of the ' nected a circuit 10. The circuit 10 contains the coil 411 is connected by a conductor 14A to the terminal G of the detecting s stem. One end 14 of the coil 12 is connecte by a conductor 15 to the terminal F of the detecting system. -The other ends 16, 17 of.

the coils 11, 12 are connected together by a conductor 18, so that the twol coils are connected in series in a circuit connected be-A tween the terminals G and F of the detecting system. A conductor 20 extends from any point of the conductor A18 to the ground. A variable condenser 21 is shunted across the coil 11 by conductors 22, 23.

The two inductancefcoils 11, 12 'are positionedfor mutual inductance and are mounted for relative movement, so that the inductance linkage between them may be changed.

In the found mostconvenient and satisfactory in practice, the two inductance coils 11, 12 are provided by astandard short wave variom- -eter in which the coils are mounted so as tuned more sharply by varying the capacity of the condenser 21, and in this way si nals of wave lengths dierent from that o the desired signals is tuned out. In the modified grounded circuit' illusform of the apparatus which I have.

trated in Fig. 2, the two :inductance coils 11',

12 which replace the coils 11, 12 of 1 shall not attempt to describe all the changes are mounted side by side instead of one Within the other, and their inductance linkage is varied by swinging one or both of the coils about pivots 24 so as to vary the distance between the coils.

I Wish it clearly understood that my in vention is by no means limited to the specific arrangement which has been illustrated and described, as I believe my invention provides the first successful receiving apparatus using neither an aerial, nor a loop, and having only one connection to the ground. YVhile I which may be made in the circuit described without departing from my invention, I wish to note that the apparatus may be made to operate without the use of the condenser 21. Y

lVhat I claim is: l

1. Radio receiving apparatus, comprising the combination with a detecting system, otl a circuit connecting the in-put terminals of said system and containing two'inductance coils connected in series and mounted for relative movement to vary the inductance linkage between them, and a connection from a point of said circuit between said coils to the ground.

2. Radio receiving apparatus, comprising the combination with a detecting system, of a circuit connecting the Ain-put terminals of said system and containing two inductance coils connected in series and mounted for relative movement to vary the inductance linkage between them, a variable condenser shunted across one of said coils, and a connection from a point of said circuit between the coils to the ground.

3. Radio receiving apparatus, comprising the combination with a detecting system containing a three element vacuum tube and having two in-put terminals which are connected with the grid and filament elementsof said tube respectively, of a circuit connectingtbe in-put terminals of said system and containing two inductance coils connected in series and mounted for relative movement so as to vary the inductance linkage between them, a connection from a point of said circuit between said coils to'the ground, and a variable condenser connected between said poin of they circuit and the grid terminal of the detecting system. i

In testimony whereof I have hereunto set m hand.

y OGDEN MINTON. 

